1. Field of the Invention
This invention relates to a demodulator for detecting binary signals from analog signal inputs, and more specifically to an integrated circuit demodulator in an FSK modem for demodulating input FSK mark and space signals.
2. Description of the Prior Art
In the past, such demodulation has been achieved through various demodulating circuits including discrete component circuits. Also, demodulation has been achieved through the use of bipolar transistors. Often, half wave rectification has been utilized.
This invention utilizes field effect transistors, specifically metal oxide semiconductor field effect transistors (MOSFETs) and a pair of full wave rectification circuits where one incoming signal is positively rectified and the other is negatively rectified. One incoming signal is attenuated in the presence of the other. The signals are summed, providing a difference which is representative of a binary value.